1. Summary of the Invention
The present invention relates to an automated measurement system and methods for measuring the size and shape of glass sheets.
2. Description of the Related Art
In processes for manufacture of glass in sheet form, it is necessary to be able to inspect the sheets of glass for defects. It is important to be able to conduct the inspection on-line in the manufacture process, at production speeds, so that defects may be rapidly identified, this information communicated with production personnel and the glass sheets with defects may readily be separated in an effective manner from glass sheets meeting quality specifications.
During the production of glass sheets, it is important that the glass sheet produced be of a precise size and shape. Glass sheets are currently produced in a variety of specified sizes and shapes. Current inspection of glass sheets for various geometries, including size and shape, in the glass production industry is semi-automated and involves mechanical fixtures or dyes, limited caliper measurements and sampling a subset of production for inspection. Pencil probes can also be used to directly mechanically measure the size and shape of an individual glass sheet. Current inspection systems for glass sheets of various geometries often rely on human measurement and human intervention with the production line to alter upstream parameters of a glass production system. Such manual processes introduce a large amount of variability in the outgoing inspection product. Until recent advances in large area sensors, attempts at precision, non-contact measurements of large area glass sheets using machine vision required multiple sensors. However, the use of multiple sensors imposes problems of camera to camera registration and the inherent loss of accuracy.
A need exists for an automated inspection system which determines the size and shape of a glass sheet.